The present invention relates to systems and methods for promoting ischemic preconditioning in individuals. More particularly, the present invention relates to systems and methods for promoting ischemic preconditioning in individuals by exercise treatments that coordinate a breathing regimen with cycles of alternating stress and relaxation.
Ischemic preconditioning is one of the most remarkable phenomena known to medical science. Brief periods of ischemiaxe2x80x94a local shortage of oxygen-carrying blood supply, in biological tissue, renders that tissue more resistant to subsequent ischemic insults.
Ischemic preconditioning has been observed in myocardial tissue of dogs who were pretreated by alternately clamping and unclamping coronary arteries to intermittently turn off the blood flow to the heart. Dogs who were treated with an optimal number of four cycles of five-minute coronary occlusion followed by five-minute reperfusion, exhibited 75% smaller infarct sizes resulting from a subsequent forty-minute coronary occlusion. Fewer than four cycles of coronary occlusion resulted in insufficient preconditioning, more than four cycles did not provide further benefit.
Myocardial tolerance also develops in response to treatment that does not include coronary occlusion (i.e., ischemia) but increases demand for oxygenated blood. In dogs, a treatment comprising of five five-minute periods of tachycardia alternating with five minutes of recovery has been shown to reduce infarct sizes.
The myocardial resistance to infarct resulting from brief periods of ischemia has also been described in other animal species including rabbit, rat and pig. Ischemic preconditioning has also been demonstrated in humans. A second coronary occlusion during the course of coronary angioplasty often results in less myocardial damage than the first. Naturally occurring ischemic preconditioning of the myocardium has been found in humans suffering from bouts of angina.
Ischemic preconditioning occurs not only in myocardial tissue but also occurs in non-cardiac tissue including kidney, brain, skeletal-muscle, lung, liver and skeletal tissue. Further myocardial resistance to infarct exists even in virgin myocardium tissue following brief ischemia in spatially remote cardiac or non-cardiac tissue. Ischemic preconditioning also exhibits a temporal reach: An early phase develops immediately within minutes of the preconditioning ischemic injury and lasts for a few hours, and a late phase develops with circadian regularity twenty four hours later and reappears cyclically over several days, and then dissipates.
The spatial and temporal characteristics of ischemic preconditioning may be a manifestation of complex interactions between various underlying phenomena that are internal as well as external to the human body. However, the biochemical and cellular mechanisms underlying the phenomena of ischemic preconditioning are not yet fully understood despite several research efforts. These research efforts have been motivated at least in part by the hope of developing pharmaceutical drugs which would provide the anti-infarct effect of ischemic preconditioning. Though ischemic preconditioning in a bottle may be desirable, it is as of now a chimera.
In contrast to a pharmacological approach to medicine, a general non-pharmacological approach to improving an individual""s physiological condition is based on physical exercise. Dardik, U.S. Pat. Nos. 5,007,430, 5,800,737, 5,163,439, and 5,752,521, and Dardik, U.S. patent application Ser. No. 09/609,087, which are hereby incorporated by reference in their entireties, elaborate on non-pharmacological exercise treatments. The exercise treatments described in Dardik are based on a perspective view of human physiology that recognizes the wave nature of cardiac activity. For example, cardiac activity manifests itself through repetitive pulsations of the heart as a heart wave. The heart wave is a result of a superposition of many underlying waves (i.e., cycles) including behavioral waves (e.g., energy expenditure and recovery cycles in response to physical activity), environmental waves (e.g., day-night cycles), and internal waves (e.g., molecular biological, cellular, and chemical cycles). The exercise treatments described by Dardik may target specific heart wave properties to enhance an individual""s overall physiological condition. For example, the treatments seek to beneficially increase heart rate variability.
However, neither of these exercise treatments nor any other in the prior art directly target ischemic preconditioning, for example, for improved myocardial behavior.
It is desirable to have systems and methods for promoting ischemic preconditioning in individuals. Recognition of cardiac activity as wave phenomenon that results from a superimposition of the effects of various endogenous and exogenous phenomena on human physiology is consistent with an empirical understanding of the spatial and temporal characteristics of ischemic preconditioning. This recognition may enable non-pharmacological treatments that provide individuals with protective powers of ischemic preconditioning for both prophylaxis and therapy.
It is an object of the present invention to provide systems and methods for providing ischemic preconditioning in individuals.
It is a further object of the present invention to provide non-pharmacological and non-invasive treatments with the goal of promoting ischemic preconditioning in individuals in order to enhance health, performance and longevity.
These and other objects of the invention are accomplished in accordance with the principles of the present invention by providing systems and methods for providing exercise treatments that can use individualized breathing exercise regimens for promoting ischemic preconditioning. The exercise regimens can include one or more exercise sessions. Each session can consist of breathing sequences co-ordinated with one or more stress-relaxation cycles. The breathing sequences can consist of one or more breathing cycles designed to induce at least one incidence of ischemia in the individual. The breathing cycles can be defined, for example, by defining time periods for inhalation, exhalation, holding breath, and not inhaling following exhalation. Each of these cycles may be defined with respect to changes in the heart rate and predetermined exercise regimens including stress-relaxation cycles.
The stress-relaxation cycles of the exercise regimens, in accordance with the present invention, can be based, for example, on therapeutic and bio-rhythmic feedback principles taught by Dardik, U.S. Pat. Nos. 5,007,430, 5,800,737, 5,163,439, and 5,752,521, and Dardik, U.S. patent application Ser. No. 09/609,087. The stress-relaxation cycles can consist of one or more cycles, during which the individual attempts to increase his or her heart rate, for example, to a target heart rate.
The periods of stress in the stress-relaxation cycles correspond to periods of high metabolic demand for oxygen in the individual""s body tissues. The breathing sequences of the exercise regimens, in accordance with the present invention, can include one or more breathing cycles that control the time periods during which the individual""s blood is oxygenated. By coordinating periods of oxygenation and non-oxygenation with periods of high metabolic demand, the breathing sequences can cause a sufficient degree of oxygen deprivation in the body tissues to cause ischemia. The timing and duration of non-oxygenating phases can be designed to control the intensity and duration of oxygen deprivation to produce ischemia in specific body tissue types such as myocardial, lung, skeletal-muscle, brain, and muscle tissues, etc., and any combination thereof.
One or more incidents of ischemia can be repeated at suitable intervals in one or more exercise sessions to provide optimal ischemic preconditioning.
The breathing exercise regimens can be synchronized with endogenous and exogenous cyclical phenomena in accordance with this invention by application of the principles for therapeutic treatment taught by Dardik, U.S. Pat. No. 5,800,737. For example, the breathing exercise treatments may be synchronized with circadian waves to provide ischemic preconditioning at periods later than the ischemic incidents themselves.
The breathing exercise regimens can also be designed to provide non-ischemic myocardial tolerance by increasing oxygen demand. Oxygen demand can be increased by sequences of rapid deep breathing cycles that substantially increase the individual""s heart rate. Alternatively, oxygen can be increased or decreased by respectively increasing or decreasing the oxygen content of the subject""s environment. Changes in the oxygen content may be performed in a preferably pre-determined cyclical fashion. A system for cycling the oxygen environment of an individual may, for example, be a hypo/hyper baric chamber. Such a chamber should preferably include the capacity to increase or decrease the oxygen content of the atmosphere within the chamber.
According to one embodiment of the present invention, an exercise treatment for promoting ischemic preconditioning can be conducted using an apparatus to monitor and analyze physiological parameters. The analysis of physiological parameters can be used to provide individualized breathing exercise regimens to promote ischemic preconditioning. The exercise treatment can include one or more exercise sessions. In the exercise sessions, the individual can be subject to one or more stress-relaxation cycles during which metabolic demand for oxygen in body tissues increases. A physiological parameter such as blood oxygen saturation level that is indicative of ischemia, i.e., oxygen deprivation, in body tissue may be monitored during a stress-relaxation cycle. A time trace of parameter data is recorded in an electronic file. Then, the time trace is analyzed, for example, to assess parameter values relative to ischemic thresholds. The analysis can determine breathing cycle parameters and stress-relaxation cycle parameters that can cause ischemic incidents. These parameters can then be used to co-ordinate breathing sequences with one or more stress-relaxation cycles to generate individualized breathing exercise regimens that promote ischemic preconditioning.
According to another aspect of this invention, electronic networks, such as the Internet, can be used to receive data and provide information to the individual remotely.